Too much gap between the tooltip and the hotspot on demo page.

There seems to be too much gap on the hotspot and the tooltip, see screenshot below:

![screen shot 2018-10-16 at 3 13 09 pm](https://user-images.githubusercontent.com/1410147/46989141-649ae480-d158-11e8-9290-5af42c559ce9.png)


